Attapulgite based LiCl composite adsorbents for cooling and air conditioning applications

A series of attapulgite-based LiCl composites were prepared with mixing method, incorporating hygroscopic LiCl into porous surface of attapulgite clay. Sorption properties of these composites were performed with high vacuum gravimetric method, desorption performance by TG-DTA analysis, and characterization by X-ray diffraction. The results show that both attapulgite structue and chloride content play prime roles in water adsorption on the AT-LiCl adsorbents, especially during lower water pressure, while at higher pressure, adsorption performances strongly depend on chloride content. At 1500 Pa, water loading on AT-LiCl (30%) can be as high as 0.44 kg/kg, while at 750 Pa, the loading is 0.31 kg/kg, which is higher than commonly used zeolite 13x and silica gel. Based on sorption equilibrium curves, isosteric heat is calculated. This study shows that intension of water sorption on composite adsorbent is intermediate between that on zeolite 13x and silica gel. The composites can be effectively regenerated during 170-190 degrees C. At-LiCl (30%) seems to be an efficient candidate for cooling or air conditioning applications, specially when utilization of heat sources at temperatures lower than 170 degrees C. (C) 2008 Elsevier Ltd. All rights reserved.